A. Field of the Invention
The present invention relates to lighting and, in particular, to apparatus, systems, and methods for producing lighting and lighting effects that simulate the appearance of a flame or flames.
B. Problems in the Art
Artificial lighting continues to advance. The advent of solid-state light sources such as LEDs has spurred further innovation.
The design of light sources for illumination purposes occupies a substantial amount of the marketplace. Use of artificial light for particular lighting effects is another major commercial area.
One particular area for lighting effects involves simulation of the appearance of flames. There has been a long-felt need for the same. This comes from both safety concerns associated with real flames in such things as candle-based fixtures, gas lamps, or wood burning or gas flame fireplaces, as well as consumer-driven desire for the aesthetic and ornamental appearance of flames.
One attempt at simulated candle flames uses an incandescent single-candle-flame-sized bulb with multiple filaments. A circuit switches between the filaments to simulate a jumping candle flame. However, they have had limited success in the marketplace. It is difficult to produce a realistic flame simulation. It is also difficult to expand the effect beyond the single bulb.
Bigger systems utilize such things as steady-state light sources but with moving or rotating mirrors, reflectors, or lenses. They are relatively complex. They involve the cost and complexity of moving parts and, again, have limited success in realistic simulation.
Attempts at using artificial light sources for log-fire flame simulation in such application as fireplaces also have limitations. Some are essentially or predominantly two-dimensional in the sense the simulation is in a vertical plane across a length and height in the fireplace. This might be deemed sufficient by some because most viewing-angles of a fireplace are towards perpendicular to that plane. Such two-dimensional solutions lack realistic simulation, particularly for shallower viewing angles relative that vertical plane. Some use lights and mechanical devices. One example is a fan to blow illuminated red and/or yellow silk ribbons vertically. The waving of the ribbons is intended to provide the flame simulation. This has limited three-dimensional effect and limited realism. It also creates noise and additional electrical power consumption over and above just lights. Some fireplace attempts utilize light sources (incandescent or LED) to illuminate or edge-light a flat panel or screen. The lights can be varied in intensity or color to try to simulate flames at or in the panel or screen. This is a two-dimensional solution which, again, works against realism in the simulation. Some solutions play either a simulation or actual video of flames on a digital display. Again, this is two dimensional.
Some flame-effect lights use solid-state sources such as LEDs which have a smaller form factor and improved effective lives over sources like incandescent sources. In some cases, they can also represent energy savings. Furthermore, driving them to different intensities that can change quickly is possible. However, again, with regard to special lighting effects such as flame simulation, the state-of-the-art has concentrates on 2D solutions or utilizing rotating optical devices relative the sources.
It can therefore be seen that a number of factors go into the design of lighting which attempts to simulate a flame or flames. Examples can include realism of simulation, cost of materials and components, operating costs, durability, and flexibility in how many forms they can take and how many different applications they can be used. Some of these factors are antagonistic with one another, making it even more difficult to reach good solutions.
For example, the combination of lights and moving parts may help simulate the look of flames, but can add capital and operating costs. It can also create noise which can be antithetical to realistic simulation or to the consumer of such devices.
The repeating patterns of most simulated flames take two dimensional forms, which allows viewers to know or perceive that they are looking at a simulated flame.
The inventor has therefore found there is room for improvement in the state-of-the-art.